Our research goals for the coming year are: 1. To continue our studies on the mechanism and mode of action of phosphate depletion on the kidney in order to delineate more precisely the sites in the distal nephron wherein phosphate depletion affects calcium transport and the mechanism whereby this occurs. 2. To study the important role of insulin and glucose on renal phosphate handling with a view towards getting insights into the fundamental transport mechanisms in the proximal tubule. 3. To initiate a series of studies on the key factors governing renal potassium secretion in the terminal nephron with a particular aim to assess more precisely the role of thiazide diuretics on renal potassium handling. 4. To investigate mechanisms of intra-renal crystalization.